Electronic Power Steering System: Other Honda Insight ZE2 рестайлинг

EPS Indicator

Under normal conditions, the EPS indicator (A) comes on when the ignition switch is turned to ON (II), then goes off after the engine is started. This indicates that the LED and its circuit are operating correctly.

If there is a failure in the system after the engine is started, the EPS indicator will stay on, and the power assist is turned off or restricted.

Scheme 82

When the EPS indicator comes on, the control unit stores the DTC. In this case, the control unit will not activate the EPS system after the engine starts again, but it keeps the EPS indicator on.

When a problem is detected and the EPS indicator comes on, there are cases when the indicator stays on until the ignition switch is turned to LOCK (0), and cases when the indicator goes off automatically when the system returns to normal.

Even though the system is operating normally, the EPS indicator will come on under some conditions with the vehicle stopped and engine at high speed with constant input from the steering wheel.

To determine the actual cause of the problem, question the customer about the conditions during which the problem occurred, taking the above conditions into consideration.

How to Retrieve DTCs

1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the EPS control unit. If it does not, go to the DLC circuit troubleshoot (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513153-S33429882062012110700000) ).
4. Follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC, refer to the DTC troubleshooting. Do the all systems DTC check and troubleshoot any powertrain DTCs first.
5. Turn the ignition switch to LOCK (0).

How to Clear DTCs

1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the EPS control unit. If it does not, go to the DLC circuit troubleshoot (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513153-S33429882062012110700000) ).
4. Clear the DTC(s) by following the screen prompts on the HDS.
5. Turn the ignition switch to LOCK (0).

System Outline

This vehicle is equipped with electrical power steering (EPS). The driver's steering force is assisted by an electric motor at the steering gearbox, instead of an engine-driven oil pump to generate oil pressure, so the EPS system improves engine efficiency.

The EPS control unit monitors and controls the EPS motor's assisting force to match driving conditions.

1. Low vehicle speeds: High power assist (for easy handling)
2. High speed driving: Low power assist (for stable driving)
3. Low speed to high speed driving: Variable assist that can change smoothly from high assist to low assist

Steering Gearbox

The steering force from the steering wheel is sent to the pinion shaft. The torque sensor measures the difference between the force applied to the pinion shaft and the resistance to turning the wheels due to road friction, and converts it to a voltage signal which is sent to the EPS control unit. Based on this signal, the EPS control unit controls the current to the EPS motor. The EPS motor shaft gear rotates the worm wheel gear which is part of the pinion shaft. This becomes the assist force in the steering system.

Scheme 83

Power relay (built into the EPS control unit)

When the system is operating normally, the CPU turns the power relay on, and the power is provided to the FET bridge. When the CPU detects a failure in the system which has the demand to shut down the system, the CPU turns the power relay off.

Fail-safe relay (built into the EPS control unit)

When the system is operating normally, the CPU turns the fail-safe relay on, and the power is provided to the EPS motor. When the CPU detects a failure in the system that requires it to shut down the system, the CPU turns the fail-safe relay off at the same time it turns the power relay off. This relay is a fail-safe in the event the power relay is faulty and does not turn off.

Electric current detection circuit

An electric current detection circuit monitors the current of the motor, and sends a signal to the CPU.

Scheme 84

Scheme 85

Scheme 86

EPS indicator does not come on

1. Turn the ignition switch to ON (II), and watch the EPS indicator. Does the EPS indicator come on? YES -Intermittent failure, the system is OK at this time. NO -Troubleshoot the gauge control module (see «SELF-DIAGNOSTIC FUNCTION»(ref-513176-S11328941922012110700000) ).

Scheme 87

Scheme 88

Scheme 89

Scheme 90

1. Turn the ignition switch to LOCK (0).
2. Check the No. 11 (7.5 A) fuse in the under-dash fuse/relay box. Is the fuse blown? YES -Replace the fuse. Turn the ignition switch to ON (II), then turn it to LOCK (0) again. If the fuse blows again, repair the short to ground on the No. 11 (7.5 A) fuse circuit. NO -Reinstall the checked fuse, then go to step 3.
3. Check the No. 2 (60 A) fuse in the battery terminal fuse box. Is the fuse blown? YES -Replace the fuse. Turn the ignition switch to ON (II), then turn it to LOCK (0) again. If the fuse blows again, repair the short to ground on the No. 2 (60 A) fuse circuit. NO -Reinstall the checked fuse, then go to step 4.
4. Do the gauge control module self-diagnostic function (see «SELF-DIAGNOSTIC FUNCTION»(ref-513176-S11328941922012110700000) ). Is the gauge control module OK? YES -Go to step 5. NO -Replace the gauge control module (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513176-S36002924502012110700000) ).
5. Turn the ignition switch to LOCK (0).
6. Disconnect EPS control unit connector C (16P) (see step 3 ).
7. Turn the ignition switch to ON (II).
8. Measure the voltage between EPS control unit connector C (16P) terminal No. 8 and body ground. Is there battery voltage? YES -Go to step 9. NO -Repair an open in the wire between the EPS control unit and No. 11 (7.5 A) fuse in the under-dash fuse/relay box.
9. Turn the ignition switch to LOCK (0).
10. Disconnect EPS control unit connector A (2P) (see step 3 ).
11. Measure the voltage between EPS control unit connector A (2P) terminal No. 2 and body ground. Is there battery voltage? YES -Go to step 12. NO -Repair an open in the wire between the EPS control unit and No. 2 (60 A) fuse in the battery terminal fuse box.
12. Check for continuity between EPS control unit connector A (2P) terminal No. 1 and body ground. Is there continuity? YES -Go to step 13. NO -Repair an open in the wire between the EPS control unit and body ground (G402).
13. Disconnect the gauge control module 32P connector (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513176-S36002924502012110700000) ).
14. Check for continuity between the EPS control unit connector C (16P) terminals and the gauge control module 32P connector terminals (see chart below). Sign EPS Control Unit Connector C (16P) Terminal Gauge Control Module 32P Connector Terminal CANL 9 19 CANH 10 20 Is there continuity? YES -Check for loose terminals in the EPS control unit connectors, and repair if necessary. If no poor connections are found, replace the EPS control unit (see «EPS CONTROL UNIT REMOVAL/INSTALLATION»(ref-513192-S06147897662012110700000) ). NO -Repair an open in the wire between the EPS control unit and the gauge control module.